It's not worse.
> a date rapist
A rapist shares 99+% of definitions and values with you as a fellow human being. AI won't (unless you somehow program them in). Rapist has his evil motivations, but won't suddenly invent a virus that kills the whole human species because you asked him to stop neighbor kids trampling your garden. AI might. If you tell it not to kill anybody it might destroy our civilization to prevent us from killing ourselves with global warming. Why not - it only makes sense.
Simplest way to ensure safety for the maximum number of human beings is to anesthetize everybody and put them on life support till their natural death. Perfect record is possible - you might cure addicts and prevent crimes and wars. If you specify people have to be awake as often as they usually are - it can keep them awake but restrained. You want people to have freedom of movement? Ok - you just released the whole prison population :) Keeping criminals in prison is OK? Then it may make everybody a criminal for a quick fix. Or just drug everybody to WANT to be restrained. And so on, and so on.
There's infinite number of possible courses of action that we discard without consciously thinking about them because of our assumptions. You have to put these assumptions in the AI, each and every one of them, and they are very subtle and invisible for us most of the time. And they often border on philosophy and morality, and defining them is political by definition.
It's probably impossible to code all our values and assumptions in by hand. That's a much bigger problem for safe general AI than a post-factum explanations that rub your morality the wrong way.
> Asimov's Three Laws
Are self-contradictory and useless for anything except literature.